Role of reactive oxygen species and superoxide dismutase in cartilage aging and pathology

Statistical development and in vivo evaluation of resveratrol-loaded topical gel containing deformable vesicles for a significant reduction in photo-induced skin aging and oxidative stress

OBJECTIVE

The present study aims to formulate and evaluate a novel vesicular formulation of resveratrol to achieve its dermatological benefits in terms of antiphotoaging and antioxidant.

METHOD

In this study, resveratrol-loaded deformable vesicular gel was prepared and optimized using Box-Behnken design. Selected critical material attributes were amount of phospholipid (X1), concentration of ethanol (X2), and amount of sodium cholate (X3). The prepared transethosomal vesicles were incorporated into carbopol gel base and evaluated. Ultraviolet radiation-induced skin aging and oxidative stress model in Swiss Albino mice was used to evaluate the clinical potential of the developed formulation and compared with conventional gel. Levels of Super Oxide Dismutase (SOD), catalase, glutathione peroxidase, protein content, and malondialdehyde were measured to assess the extent of lipid peroxidation and reactive oxygen species inhibition in different groups.

RESULT

DoE was successfully employed to optimize the vesicular formulation. Vesicle size was found to be 158.9 ± 7.65 nm, while values of entrapment efficiency and skin deposition were found to be 77.83 ± 2.87% and 371.84 ± 5.12 µg cm^-2, respectively. Visual skin grading and histopathological studies confirmed the higher efficacy of transethosomal resveratrol against oxidative stress. Significant enhancement in the levels of antioxidant enzymes and protein content confirmed the ameliorated potential of flexible transethosomal resveratrol as compared to the plain gel of resveratrol.

CONCLUSION

Restoration of first-line defense mechanism in chronic UV-exposed animal model has proved that transethosomal resveratrol can be developed as an innovative cosmetic product for significant improvement and repair of photo-aged skin.

A small molecule promotes cartilage extracellular matrix generation and inhibits osteoarthritis development

Degradation of extracellular matrix (ECM) underlies loss of cartilage tissue in osteoarthritis, a common disease for which no effective disease-modifying therapy currently exists. Here we describe BNTA, a small molecule with ECM modulatory properties. BNTA promotes generation of ECM components in cultured chondrocytes isolated from individuals with osteoarthritis. In human osteoarthritic cartilage explants, BNTA treatment stimulates expression of ECM components while suppressing inflammatory mediators. Intra-articular injection of BNTA delays the disease progression in a trauma-induced rat model of osteoarthritis. Furthermore, we identify superoxide dismutase 3 (SOD3) as a mediator of BNTA activity. BNTA induces SOD3 expression and superoxide anion elimination in osteoarthritic chondrocyte culture, and ectopic SOD3 expression recapitulates the effect of BNTA on ECM biosynthesis. These observations identify SOD3 as a relevant drug target, and BNTA as a potential therapeutic agent in osteoarthritis.

Superoxide dismutase 3 facilitates the chondrogenesis of bone marrow-derived mesenchymal stem cells

Articular cartilage defects are considered a major clinical problem because they cannot heal by themselves. To date, bone marrow-derived mesenchymal stem cells (BMSCs)-based therapy has been widely applied for cartilage repair. However, fibrocartilage was often generated after BMSC therapy; therefore, there is an urgent need to stimulate and maintain BMSCs chondrogenic differentiation. The specific role of superoxide dismutase 3 (SOD3) in chondrogenesis is unknown; therefore, the present study aimed to clarify whether SOD3 could facilitate the chondrogenic differentiation of BMSCs. We first evaluated SOD3 protein levels during chondrogenesis of BMSCs using plate cultures. We then tested whether SOD3 could facilitate chondrogenesis of BMSCs using knockdown or overexpression experiments. Increased SOD3 protein levels were observed during BMSCs chondrogenesis. SOD3 knockdown inhibited collagen type II alpha 1 chain (COL2A1), aggrecan (ACAN), and SRY-box 9 (SOX9) expression. Overexpression of SOD3 increased the levels of chondrogenesis markers (COL2A1, ACAN, and SOX9). Elevated superoxide anions were observed when SOD3 was knocked down. We concluded that SOD3 could facilitate chondrogenesis of BMSCs to improve cartilage regeneration.

Recent Progress in Micro/Nanoreactors toward the Creation of Artificial Organelles

Artificial organelles created from a bottom up approach are a new type of engineered materials, which are not designed to be living but, instead, to mimic some specific functions inside cells. By doing so, artificial organelles are expected to become a powerful tool in biomedicine. They can act as nanoreactors to convert a prodrug into a drug inside the cells or as carriers encapsulating therapeutic enzymes to replace malfunctioning organelles in pathological conditions. For the design of artificial organelles, several requirements need to be fulfilled: a compartmentalized structure that can encapsulate the synthetic machinery to perform an enzymatic function, as well as a means to allow for communication between the interior of the artificial organelle and the external environment, so that substrates and products can diffuse in and out the carrier allowing for continuous enzymatic reactions. The most recent and exciting advances in architectures that fulfill the aforementioned requirements are featured in this review. Artificial organelles are classified depending on their constituting materials, being lipid and polymer-based systems the most prominent ones. Finally, special emphasis will be put on the intracellular response of these newly emerging systems.

Articular Cartilage Aging-Potential Regenerative Capacities of Cell Manipulation and Stem Cell Therapy

Changes in articular cartilage during the aging process are a stage of natural changes in the human body. Old age is the major risk factor for osteoarthritis but the disease does not have to be an inevitable consequence of aging. Chondrocytes are particularly prone to developing age-related changes. Changes in articular cartilage that take place in the course of aging include the acquisition of the senescence-associated secretory phenotype by chondrocytes, a decrease in the sensitivity of chondrocytes to growth factors, a destructive effect of chronic production of reactive oxygen species and the accumulation of the glycation end products. All of these factors affect the mechanical properties of articular cartilage. A better understanding of the underlying mechanisms in the process of articular cartilage aging may help to create new therapies aimed at slowing or inhibiting age-related modifications of articular cartilage. This paper presents the causes and consequences of cellular aging of chondrocytes and the biological therapeutic outlook for the regeneration of age-related changes of articular cartilage.

Aiding nature's organelles: artificial peroxisomes play their role

A major goal in medical research is to develop artificial organelles that can implant in cells to treat pathological conditions or to support the design of artificial cells. Several attempts have been made to encapsulate or entrap enzymes, proteins, or mimics in polymer compartments, but only few of these nanoreactors were active in cells, and none was proven to mimic a specific natural organelle. Here, we show the necessary steps for the development of an artificial organelle mimicking a natural organelle, the peroxisome. The system, based on two enzymes that work in tandem in polymer vesicles, with a membrane rendered permeable by inserted channel proteins was optimized in terms of natural peroxisome properties and function. The uptake, absence of toxicity, and in situ activity in cells exposed to oxidative stress demonstrated that the artificial peroxisomes detoxify superoxide radicals and H2O2 after endosomal escape. Our artificial peroxisome combats oxidative stress in cells, a factor in various pathologies (e.g., arthritis, Parkinson's, cancer, AIDS), and offers a versatile strategy to develop other "cell implants" for cell dysfunction.

Enzymatic cascade reactions inside polymeric nanocontainers: a means to combat oxidative stress

Oxidative stress, which is primarily due to an imbalance in reactive oxygen species, such as superoxide radicals, peroxynitrite, or hydrogen peroxide, represents a significant initiator in pathological conditions that range from arthritis to cancer. Herein we introduce the concept of enzymatic cascade reactions inside polymeric nanocontainers as an effective means to detect and combat superoxide radicals. By simultaneously encapsulating a set of enzymes that act in tandem inside the cavities of polymeric nanovesicles and by reconstituting channel proteins in their membranes, an efficient catalytic system was formed, as demonstrated by fluorescence correlation spectroscopy and fluorescence cross-correlation spectroscopy. Superoxide dismutase and lactoperoxidase were selected as a model to highlight the combination of enzymes. These were shown to participate in sequential reactions in situ in the nanovesicle cavity, transforming superoxide radicals to molecular oxygen and water and, therefore, mimicking their natural behavior. A channel protein, outer membrane protein F, facilitated the diffusion of lactoperoxidase substrate/products and dramatically increased the penetration of superoxide radicals through the polymer membrane, as established by activity assays. The system remained active after uptake by THP-1 cells, thus behaving as an artificial organelle and exemplifying an effective approach to enzyme therapy.